burned dumpling mystery

I made gluten free dumplings with Pamela's gluten free all purpose baking mix. Just the flour mix and some milk. And they looked beautiful and perfect on the outside but were dark brown and doughy dense on the inside. Any idea what causes this? I found one other place online where someone had this issue and was quite frustrated. It happened to them twice using the same recipe that had never been a problem many time before.
The only suggestion there was a bad egg in their ingredients. But mine had no eggs.
Could it have been that the milk in the recipe scalded? So disappointing. (the rest of the soup was perfect! Made with homemade bone broth)

Many gluten free blends are made of starches that, while extremely high in "sugars", are also very hygroscopic, which means they absorb and hold onto a healthy amount of liquid. The time it takes for them to cook through, they may be burning. Are you covering the pot? Are you cooking them slowly? How large are you making them? Maybe a typical dumpling size might be too large to cook evenly. Try maybe smaller?

I have to say, I'm always wary of "all-purpose mixes", because as the old saying goes "A jack of all trades a master of none"...they often don't do anything well enough to be as useful as they claim to be. Have you tried other blends? This one appears to be really complicated (11 ingredients!). I really love Cup4Cup flour for relatively seamless GF cooking.

O great suggestions! Thank you! This was only my 3rd time making dumplings and had not had this problem before. I think I used different mixes in the past but it was a while ago and I can't recall.
This helps. I didn't know where to start. The dumplings were about a T+ scoop.
I put them into plain simmering water first because I don't like how they crumbled into the soup a lot at the start in the past. Then I added them to the soup. Idk if that would create an issue but it solved that problem and I thought I was so clever.
Maybe I cooked them too hot, but many recipes say to put them in boiling soup. Was only about 30 minute.

Another way to approach the desire for GF dumplings...use those recipes whuch have been developed and confirmed by usage in places that don't rely (or not exclusively) on wheat.
Examples that come to mind are dumplings from mashed potatoes, rice and corn. Probably are more out there...